3/02/2010

30 years of QNX: The first OS to support a PC hard drive

Back in the early 1980s, I came across an IBM XT equipped with a "whopping" 10MB hard drive. The drive alone cost $3000, which at the time amounted to one-tenth the average salary of an electrical engineer. I remember thinking, “Who the hell would need a hard drive that big?” Some people are born futurologists; I'm not one of them.

The XT in question used MS-DOS, but DOS wasn't the first OS to support a hard drive on a PC. That honor belongs to QNX, which in 1982 introduced support for a 5MB Davong. If that sounds small, you're right: it's just enough to store a single photo from one of today’s low-end digital cameras.

Supporting a hard drive wasn’t the only first for QNX. It also became the first realtime OS to support 286 protected mode, to offer distributed processing, and to run on a Compaq 386 machine.

The very first commercial version of QNX required 64K of RAM. That's only six one-hundred thousandths of a gigabyte, a gigabyte being the bare-bones configuration of a modern PC. Still, that was "enough memory to run the OS, a shell, and actually compile programs... it was even possible to do a few background chores at the same time, like printing a file.” I'm quoting from a FAQ written by veteran QNX user Mitchell Schoenbrun.

Speaking of Mr. Schoenbrun, here’s a closeup of him holding a pre-release copy of QNX — version 0.433, to be exact. If you attended the QNX 2000 users’s conference, you would have had the rare pleasure of seeing this ultra-early release running in the QNX booth:

That's right, Aliquis. QNX's main focus was always in the embedded market: cars, factory control systems, massive Internet routers, medical devices, etc. There are many millions of cars on the road today using QNX-based systems.

I am Mitchell Schoenbrun. I don't recall saying that QNX was the first OS that supported a hard drive. Even saying that it was the first that supported a hard drive on an IBM PC would be dubious. The first hard drive I recall was not a Davong. Another company whose name escapes me had three drives a 5, a 10 and a 20. These were minicomputer drives. The 5Meg was about $3000 The Davong came with a controller and was $2000 so it was great bargain. Later they also had a 10meg version. The driver was hacked into the OS, before the "mount" command came along. I'd be surprise however if Davong didn't provide a DOS driver when they released their product. Of course that would have been DOS 1.1, which had only one directory, the root. I seem to recall that you could partition it into multiple smaller disks, necessary with only a root directory.

Hi Mitchell! If you re-read the paragraph in question, you'll see that I'm referring to the quoted words, where you state that QNX required 64K of RAM. I wasn't trying to imply that you said QNX was the first PC OS to support a hard drive. My apologies if I've inadvertently left that impression. It was completely unintentional.

But to your main point, was QNX truly the first PC OS to support a hard drive? Let me see if someone at QNX more qualified than me can shed light on the issue. This is a longstanding claim, and now I'm intrigued!